HISTORY OF THE CHILTERN DECORATIVE AND FINE ARTS SOCIETY
70
pages
English
Documents
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
70
pages
English
Documents
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
- cours magistral
- cours magistral - matière potentielle : patricia
- cdfas
- crowd of women with nothing
- group of dilettante housewives
- patricia fay
- anniversary
- nadfas
- art
- group
Preliminaries I
1Agenda
Primitive types
• Operators
• Statements
• Static methods
Reference types
• Strings
• Arrays
• E xception handling
• Input and output
2The first program
Compilation: javac FirstProgram.java!
Execution: !java FirstProgram!
3Three important concepts
related to languages
• Syntax (grammar)
• Semantics (meaning)
• Pragmatics (use)
How are these concepts related to the sentence “I am hungry”?
4On the need for grammar
Alan Creak (2002)
When learning our first natural language we spend long periods
hearing the language (or noise) and seeing it in the context of
other people’s actions, and from this we learn the structure of
the language, and how it is related to what happens in the
world. We might not know the rules, but we learn how the
language machine works.
In programming, not only have we no experience of the world
we’re in; we have no experience of others operating in that
world, so we are stuck with grammar.
5Types
A type is a set of legal values
A variable refers to a location in memory where a value can be stored
Each variable is associated with a type. The variable type restricts the
values that the variable may hold.
The types in Java are divided into two categories:
(1) Primitive types
(2) Reference types
6Primitive types
7Constants (literals)
An integer constant may be written in
decimal notation: 23
octal notation: 027
hexadecimal notation: 0x17
Floating-point constants are written as a decimal number with an
optional exponent part:
3.24 3.24e5 3.24e-5
3.24f 3.24d
Character constants are written directly between single quotes:
'z' '\u007A' '\712'
' \n ' ' \t '
' \ ' ' ' \" ' '\\'
8Declaration and initialization
Any variable, including those of primitive types, is declared by
providing its name, and optionally, its initial value.
Examples:
int num1;!
!double minimum = 4.50;!
!int x = 0, num2 = 2;!
!int num3 = 2 * num2;
9Basic operators
10
